Shipping container and method of construction thereof

ABSTRACT

An intermodal shipping container including one or more improvements such as intermediate gable posts or gable headers adapted to increase an internal width and strength of the container, wherein the gable posts or the gable headers include twin channels having at least two internal flanges welded to a gable post plate or gable header plate, one or more upper castings having an integral top rail ledge, wherein a top rail of a side wall hangs on the integral top rail ledge, “C” channel style beam main frame cross members, a one-piece continuous top plate including an integral lip connecting the top plate and a roof, one or more rear lower castings, wherein the one or more rear lower castings are an integral interlocking interface, a bolster including an integral seating and fastening surface and slots, and/or one or more nested rear corner posts subassemblies, the one or more nested rear corner posts having a notch and protrusion connection, wherein a protrusion in a lower rear casting engages with a corresponding notch in the rear corner post.

This application claims priority to U.S. Provisional Patent Application No. 63/076,061 filed Sep. 9, 2020, entitled “SHIPPING CONTAINER AND METHOD OF CONSTRUCTION THEREOF,” which is hereby incorporated by reference herein.

The present invention relates to reusable intermodal shipping containers.

BACKGROUND OF THE INVENTION

Containers are used to transport materials. The containers may be transported by trucks on the highway, by trains on the railway and or by nautical vessels, for example. They may be individual or stacked on top of one another.

The basic design of intermodal containers has changed very little over the past 25 years. In fact, the performance of some current containers may have actually been compromised to achieve some of the (customer requested) design targets to such a point that they very likely no longer meet the required loading/stacking/handling requirements as mandated by AAR M-930 (or similar/equivalent governing industry standards).

U.S. Publication No. 20070051719, U.S. Publication No. 20140069912 and U.S. Publication No. 20140144922, all teach commercial storage and transport containers having a roof, side wall, floor, and one or more support structures. However, many problems still exist with containers.

The inventive design of the present invention greatly improves the strength of the container and also eliminates “chronic” issues that have not been addressed or resolved over the past 25 years. Additionally, some of the inventive attributes will also likely increase the anticipated service life of the container.

SUMMARY OF THE INVENTION

The present invention provides a reusable intermodal shipping container for use on highway, railway, and nautical transportation to contain, store, and protect cargo during transport. For highway use, it is coupled with a dedicated chassis that is pulled by a tractor (semi). For rail use, it is either set into the cavity within a well rail car, set on a flatbed car, or it is stacked on top of, and connected, to another intermodal container already in these locations. They can also sit on a chassis that is sitting on a flatbed car. In general, the design permits all intermodal containers to be stacked on top of and connected to other intermodal containers.

The present invention provides a reusable intermodal shipping container, containing enhanced design features permitting greater interior cargo volume while having a reduced overall tare weight (container mass) and delivering superior performance and an anticipated increase to expected service life.

The present invention provides an intermodal shipping container including one or more intermediate gable posts (also known as staking or intermediate posts) and/or intermediate gable headers adapted to increase an internal width and strength of the container, wherein the gable posts and/or the gable headers include twin channels having at least two internal flanges welded to a gable post plate and/or gable header plate.

The present invention also provides an intermodal shipping container including one or more upper castings having an integral top rail ledge, also referred to as a seat, wherein a top rail of a side wall hangs on the integral top rail ledge.

The present invention also provides an intermodal shipping container including “C” shaped channel beam main frame cross members.

The present invention also provides an intermodal shipping container including front and rear bolsters including an integral seating and fastening surface and slots, the integral seating and fastening surface adapted to fasten and support flooring and the slots used for welding, wherein the bolster is flush with a top surface of flooring.

The present invention also provides an intermodal shipping container including one or more nested rear corner posts subassemblies, the one or more nested rear corner posts having a notch and protrusion connection, wherein a protrusion in a lower rear casting engages with a corresponding notch in the rear corner post.

The present invention also provides an intermodal shipping container including a one-piece continuous top plate including an integral lip connecting the top plate and a roof. The top plate integral roof filler piece forms an integrated welding location for the roof panels.

The present invention also provides a shipping container having a front top plate with an integral front roof filler piece which forms an integrated welding location for the roof panels.

The present invention also provides rear headers with integral internal gussets that further enhance the strength of the header assemblies

The present invention also provides an intermodal shipping container including one or more rear lower castings, wherein the one or more rear lower castings are an integral interlocking interface, wherein a door sill abuts the rear lower casting and a rear corner post, the one or more rear lower castings having an observation hole to externally view a chassis twist lock. The rear lower casting profile increases the length of the weld interface and therefore the strength.

The present invention also provides a method of fabricating an intermodal shipping container, the method including preparing a sub assembly by welding a top rail onto a side wall panel, introducing the side wall sub assembly to intermediate gables from above, and lowering the wall sub assembly until the wall assembly is entirely supported by the intermediate gables

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a 53′ Intermodal Shipping Container of the present invention;

FIGS. 2A and 2B show a conventional gable post design;

FIGS. 2C, 2D, 2E and 2F show exemplary embodiments for a twin channel gable design;

FIGS. 3A and 3B show a top rail ledge/seat of an interlocking feature of the present invention in the upper casting;

FIGS. 4A and 4B show main cross members of the present invention;

FIG. 5A shows a conventional rear header contact plate;

FIGS. 5B, 5C and 5D show the rear header contact plate of the present invention;

FIG. 6 shows a rear header door assembly/weldment of the present invention;

FIGS. 7A and 7B show an exemplary embodiment of the rear header and bolster (or door header and door sill) with integral gussets;

FIG. 8A shows a conventional front header contact plate;

FIGS. 8B and 8C show a front header contact plate of the present invention;

FIGS. 9A and 9B show a rear lower casting of the present invention;

FIG. 10A shows a conventional intermediate bolster;

FIG. 10B shows an intermediate bolster of the present invention;

FIGS. 11A and 11B show a rear corner post of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following terminology can be defined interchangeably: 40′ gable (or just “gable”), intermediate stacking post, and stacking frame; Gable header, gable upper (or top) channel and plate assembly, intermediate header and intermediate frame upper (or top) member; Rear intermediate bolster, rear 40′ gable (or rear intermediate stacking post/frame), lower (or bottom) channel and plate assembly, and lower (or bottom) cross member; Upper casting and upper handling fitting; Lower rear casting, lower 53′ rear casting, and lower rear corner casting. The same terminology is also applicable to all size shipping containers including 60′, for example.

There are four bolsters in the floor of a container. The front bolster is the lower structural member of the front facing wall which engages with the front bolster of the associated chassis. The two, intermediate bolsters connect the lower, intermediate 40′ castings, respectively and form the lower portions of the structural “ring” of the intermediate stacking frames. Therefore, there is both a front and rear intermediate bolster. And finally, the rear bolster (sometimes referred to as a “door sill”) which rests directly upon the rear bolster of the associated chassis.

Although described as highway and railway cargo carrying shipping containers throughout the specification, the present invention is not limited to such use. Various aspects for this invention can be used in other applications and/or industries.

FIG. 1 shows a shipping container of the present invention having roof 6, front wall/door 4 and side walls 8.

FIGS. 2A and 2B show an existing gable post design including twin external channels 23 and upper casting 21. Weld 27 is applied using industry best welding practices on both sides of channels 23, for example a groove weld. Weld 25 is also used and runs at the top of touching channels 23. Extensions 29 provide additional surface for wall panel welds.

FIGS. 2C, 2D, 2E and 2F show twin channel gable posts and gable header designs of the present invention. Twin channel designs may include channels that are standard, mirrored, symmetrical or other differing shapes. Twin channels 24 permit two additional internal flanges, which serve as internal gussets, to provide a significant increase to the resistance to bending/buckling when the container has additional containers stacked on top of it in rail, yard, or nautical applications. Twin abutted flanges of channels 24 significantly increase the section modulus. Twin abutted flanges are suitably welded (e.g., plug welded) to gable post plate 22 through slots 26 creating a twin “boxed” design that is strong and stiff. Twin abutted flanges of channels 24 significantly increase load paths L for stress transmission from upper casting 20 to the lower casting. Similarly, the lower 40′ intermediate casting (not shown) also has a corresponding interlocking member, such as a protrusion that allows for completely interchangeable placement of the twin channels and easier production and material handling. The design of the present invention allows the interior width of the container to be increased, increasing the cargo carrying capacity of the container, while still meeting the loading requirements mandated by the AAR M-930 (or similar/equivalent governing standards). The design can also be used on containers having conventional interior widths (less than 100½″). The twin channel design and abutted flanges is also extended to the gable header plates 28 as well which increases the strength of the top of the container permitting the use of thinner and lighter roof panels, such as 1.1 mm, for example, further reducing tare weight of the container while still meeting the strength requirements mandated by the AAR M-930 (or similar/equivalent governing standards).

Current container interior widths are generally limited to 99″. In a conventional, high cube 53-foot container, this limits interior volumetric payload capacity to approximately 3950 cubic feet. The present invention can be used with any length container, including in particular 60′ lengths. In the 53′ embodiment described herein, a container with an internal width of 100½″ is enabled. This will permit an increase of volumetric payload capacity to approximately 4013 cubic feet (approximately a 1.5% increase) in a 53′ length embodiment, and more in larger containers. To facilitate this width increase, an enhancement to the 40′ gable posts are used with a twin channel design to provide the 100½″ wide container with equivalent strength to the conventional 99″ wide container design. This makes this container more efficient to operate.

In one exemplary embodiment of the present invention, the maximum exterior width of the container is 2600 mm (102⅜″). To achieve a 100½″ inside width, the entire gable post assembly depth can only be 15/16″ each. Ultra-high strength steel, combined with optimized design and precisely controlled manufacturing geometry and welding techniques, creates a design that meets the stacking and loading requirements mandated by the AAR M-930 (or similar/equivalent governing standards).

In another exemplary embodiment of the invention, a single “twin” profile gable post design is shown in FIGS. 2E and 2F. The same design profile also applies to gable headers. The single twin channel designs may include profiles have differing shapes then shown that achieve the same or superior strength. The profile may be symmetrical or asymmetrical. Single twin channels 204 are welded to gable post plate 22 with welds 27, such as fillet welds, on both exterior sides of twin channels 204. Twin channel gable post has integral interior flanges located where the two sloped pieces of single twin channels 204 meet at weld 25. Single post channels 204 have a rolled or brake press profile and can be the same width W as two-piece twin channels 24 of the present invention. The single twin channel design of the present invention reduces the susceptibility to crevice corrosion, requires fewer components for handling, requires fewer welding parameters, and fits in existing manufacturing tooling. FIG. 2F shows another exemplary embodiment of a single “twin” channel gable post design which is also applicable to gable headers. Single twin channels 224 are welded to gable post plate 22 with plug welds 207 (or other suitable welds) on both sides. Slots 26 in post plate 22 allow plug weld 208 (or other suitable weld) from the inside. Twin channel gable post has integral interior flanges located where the two sloped pieces of single twin channels 224 meet at weld 208. Extensions for wall panel welding are moved to the channel portion of weldment and are integrated to single twin channels 224. This maintains a flat interior profile. The embodiment shown in 2F has additional advantages over the embodiment shown in FIG. 2E. It provides one side welding 207 on the interior of single twin channel 224 and plate 22, better alignment of post gable plates 22 as it is self-centering, and provides better control of wall panel lateral placement allowing the interior width to be easier to maintain.

FIGS. 3A and 3B show an exemplary embodiment of integral top rail ledge (or seat) 33 in upper casting 30. Upper casting 30 has an interlocking member or protrusion 35 that is integral to casting 30. It protrudes from casting 30 and engages with a corresponding interlocking member 38, or notch, in channels 32 of gable post 37 (or header 39) to increase engagement with twin channel gable post 37 or gable headers 39. This allows for a greater weld length and enhances the strength of this critical connection. Bottom face of ledge (or seat) 33 allows top rail 34 of the walls to “sit” on and be located by an integral feature (with cast components). Ledge 33 is cast into upper casting 30 and requires no additional manufacturing processes to benefit from upper casting 30, whereas in the prior art, the top rails abut the upper casting. Ledge 33 creates a seat for top rail 34 to rest against. Top rail 34 wall assembly hangs from upper casting 30. When loaded, top rail 34 (rectangular tubing shown as one embodiment) is subjected to shear forces as opposed to the weld joints connecting the top rails to the upper castings in the prior art. This provides a stronger connection. Vertical face of cast-in ledge 33 helps control side wall sub-assemblies' lateral location during manufacturing helping to maintain interior width.

In addition to conventional manufacturing, the present invention also provides a more efficient manufacturing process. During fabrication, top rail 34 is welded onto side wall panels 36. This sub assembly is then incorporated into the container assembly during subsequent assembly steps. Side wall sub-assemblies 36 can be introduced to the intermediate gables from above and lowered in place until side wall sub-assemblies 36 are entirely supported by the intermediate gable 37. This makes fabrication easier and more efficient. Vertical face of cast in ledge 33 helps control side wall sub-assemblies' lateral location during manufacturing helping to maintain interior width. Alternatively, top rail 34 can be welded in place (creating a exoskeleton) and then side wall panels 36 would be welded in place.

FIGS. 4A and 4B show an exemplary embodiment of main frame cross member sections 46 under floor 40. Cross members 46, which are not a conventional C beam, but are a shape having a C section, are an improvement over the conventional “I” beam configuration. Cross members 46 have the same sectional depth and width as conventional “I” beam construction and provide a stronger frame having the same overall mass. Cross members 46 have an increased resistance to bending and torsion over conventional “I” beam construction. Another advantage to the channels of the present invention over the conventional “I” beams, is the web can be oriented to face the front of the container (the open section facing the rear of the container). This eliminates the air trap created when using an “I” beam section. Eliminating this air trap reduces the drag created during transport and improves fuel consumption from smoother airflow under the container. The newly oriented web further eliminates both the acoustical contribution of this air trap and the dirt/mud trap that can hold moisture contributing to and/or accelerating corrosion of key structural elements of the container. Additionally, the web dimension of the C shaped cross members 46, is one continuous length as opposed to those in the “I” beam that are interrupted mid span by the web itself. This allows for one continuous weld bead to fully weld the C shaped channel to the respective lower main rail, ensuring a better weld with fewer start and stops and minimizing potential variability in the welded connection. This also ensures better weld penetration and does not subject the structural members to extra heat created with additional weld joints, safeguarding the metallurgical properties of the steel. Due to the side located web, the “C” channel also allows for a wider, uninterrupted flange in which to locate floor screws. This greatly enhances installation of the floor and prevents holes from being drilled into the web, in comparison to a conventional “I” beam structure which requires holes being drilled into the web and compromises its structural integrity.

FIG. 5A shows the prior art rear contact plate 52. Contact plate 52 consists of multiple separate pieces attached to roof 56 and door header 51. FIGS. 5B, 5C, 5E and 5D show continuous one-piece rear contact plate or door header top plate 50. Door header top plate 50 includes an integral rear roof filler piece, integral lip 54, that provides a connection point for rear roof 56. Lip 54 provides a stronger roof system. Overhang 58 shields upper door rod keepers, reducing the propensity for damage of the container during use and handling. Door header top plate 50 eliminates the piece count of conventional contact plate 52 and unnecessary weld joints. Door header top plate 50 also eliminates chronic leak points and several catch points reducing the propensity of damage to the container during use and handling. Door header top plate 50 with overhang 58, as shown in FIGS. 5C and 5D, eliminates all four contact plates and associated filler pieces, numerous welding operations, and numerous potential leak points of the prior art and permits a stronger flange on which to allow the front/rear roof assemblies to rest during fabrication.

FIG. 6 shows an alternate view of door header top plate 60 with integral rear roof filler piece, integral lip 64. Integral lip roof filler piece 64 is close in the area in the roof where the structural elements of the front and rear gables meet the front and rear roof assemblies, respectively. The current practice is to weld a horizontal plate onto the top member of the front/rear gables that extends towards the inside of the container. All four exterior corners of the container require a contact plate to be present. This is conventionally achieved by welding a suitable steel piece in each corner along with multiple little filler pieces that close in openings created by the mating geometry. The present invention provides a rear lower edge 66 of the door header top plate 60 having a radiused profile to facilitate door gasket 68. The roof panel sits on integral lip 64. Door Gasket 68 on door 62 resolves the chronic problem of door gasket wear which results in water ingress into the container reducing the propensity for damage during use and increasing the service life of door gasket 68. The same door header top plate with integral roof filler can also be used on the front roof, front top plate, as seen in FIGS. 8A, 8B and 8C.

In another embodiment of the present invention, FIGS. 7A and 7B show exemplary embodiments of a rear header, door header 70 in FIG. 7A and door sill (or rear bolster) 74 in FIG. 7B. Headers 70, 74, can also have integral internal gussets 72, 76, that further enhance the strength of these assemblies. Internal gussets 72, 76, can be aligned with the door lock rod keepers, enhancing their support and security of the container when locked. In addition, there is an added advantage to the integral internal gussets 72, 76 in the rear bolster (door sill) 74. They can also be aligned with the track width of conventional forklift wheels to help resist impact loading that the rear bolster (door sill) is typically and repeatedly subjected to. Over time, this can result in the rear bolster (door sill) becoming “crushed.” A damaged rear bolster (door sill) constitutes a compromised structural integrity of the rear gable and the container as a whole system. A damaged rear bolster may not sit properly on a chassis and may impair the effective sealing of the door gasket.

FIG. 8A shows the prior art front contact plate design 81. Contact plate design 81 consists of multiple separate pieces attached to roof 86. FIGS. 8B and 8C show an exemplary embodiment of the continuous one-piece front contact plate, front top plate 80. Front top plate 80 eliminates the piece count of conventional contact plate 81 and unnecessary weld joints and potential chronic leak points. Front top plate 80 also eliminates several catch points reducing the propensity of damage to the container during use and handling. Front top plate 80 has an integral front roof filler piece, integral lip 84, that provides a connection point for front roof 86. Integral lip 84 provides a stronger roof system.

FIGS. 9A and 9B show an exemplary embodiment of a rear lower casting profile 91. Most conventional container designs have the door sill abut rear corner posts with the rear lower casting welded below. This creates a stress concentration point at this welded connection that can (and tends to) crack over time. Rear lower casting 91 prevents the stress concentration point damage by moving the stress concentration point from a welded joint to the casting itself which is now integral to the connection. An integral interlocking casting 91 is the interface between door sill 90 and rear corner post 92. Casting 91 has integral interlocking members, protrusion, 94, that interlock with corresponding interlocking members, notches 96, on members such as rear post 92 and/or door sill 90. Door sill 90 connects and sits in casting 91. Rear post 92 connects with and sits on casting 91. Casting 91 eliminates the chronic weld fatigue point. Casting 91 allows for a longer weld length joining the rear lower casting 91 to rear corner post 92. Casting 91 has a lateral observation hole 93 to view the chassis twist lock from the side of the container. This increases safety to ensure the chassis twist lock has been properly engaged when the container is in transport.

Most containers have wooden floors (some containers have aluminum or other flooring material) 102 that are fastened to structural frame elements to permanently retain the floor. FIG. 10A shows the conventional design of front or rear intermediate bolster 101. It is a channel and plate design 103 with angle irons 105. Floorboards 102 are fastened to angle irons 105. FIG. 10B shows an exemplary embodiment of a front or rear intermediate bolster 100 with integral floor supports 104 of the present invention. The intermediate bolsters form a “ring” with the intermediate gables and headers. Intermediate bolster 100 is flush with the top surface of flooring 102. Intermediate bolster 100 provides a seating and fastening surface 104 for floor 102 to attach. Flooring 102 is fastened to structural frame elements to permanently retain the floor. Floors may be made of any suitable material such as wood, plastic or aluminum. Intermediate bolster 100 reduces the piece count and eliminates the need to weld additional metal pieces, such as the weld beads required by angle irons 105. Added heat from additional weld beads negatively impacts material properties and strength of intermediate bolsters. Intermediate bolster 100 reduces the weld joints and therefore safeguards the metallurgical properties of the steel. Intermediate bolster 100 can also have integral internal gussets, similar to the rear headers, for enhanced strength. Slots 106 in Intermediate bolster 100 allow for plug (or suitable) weld beads Gussets are welded to the “hat” portion of bolster 100. During manufacturing, the gussets are welded in place inside channel 108 of bolster 100. The “hat” portion of bolster 100 is then welded to channel. Gussets in conjunction with slots 106 contribute greatly to the strength of bolster 100 once all is welded together as a sub-assembly. Gussets can be aligned with track width of conventional forklifts to prevent “crushing” of intermediate bolster 100.

Conventional containers have a channel and pressed plate rear corner post. This arrangement results in an inherent gap or void in the region between the rear corner post and the rear lower side rail, creating a dirt/mud trap that can hold moisture contributing to and/or accelerating corrosion of key structural elements of the container. Additionally, there is no way to smoothly transition the rear lower siderail to the inner edge of the rear corner post plate. In the prior art, the gap/void created can lead to a hang up point for cargo during loading/unloading and cause damage to the containers or the cargo. FIGS. 11A and 11B show an exemplary embodiment of the nested rear corner post design 111 of the present invention. Rear corner post 111 differs from a conventional rear corner post because it has interlocking members such as notch 114 and protrusion arrangement. The lower rear casting protrusion 116 engages with notch 114 located in read corner post 111. Notch 114 is located in rear corner post 111 and protrusion 116 is an integral feature of the lower rear casting 118. The shapes of the notch and the protrusion correspond with one another. The corresponding shapes of the interlocking members may be a symmetrical sloping shape, such as a trapezoid. The “trapezoidal” shape, as shown, allows the steel member to be self-centered when introduced to the casting (or vice versa) and minimizes stress concentrations caused by 90 degree angles of square shaped. The present invention eliminates gaps/voids of the prior art. In doing so, nested rear corner post 111 creates a strong door opening and eliminates problems created by voids. Rear lower side rail 115 is welded to door gable 111. With the nested design of the present invention, flange 117 is specifically provided for this weld joint. Flange 117 is also welded to the inner portion 113 of the rear corner (door) post sub-assembly. This allows for an additional weld bead to be applied to this critical corner of the container.

Currently, all intermodal containers are governed by a maximum of 67,200 lbs for the combined mass of the container and the cargo it can be loaded with and safely moved. When the tare weight of the container is reduced, it permits an increase in permissible cargo carrying capacity which is a competitive advantage to customers. Subsequently, the increase in internal volumetric payload capacity enabled by, for example, 100½″ internal width also allows for advantages, as most cargo limitations are typically volumetric in nature, not mass.

Ultra-high strength steel (100 ksi yield) preferably should be used in key locations to enable the design. Additionally, the upper castings preferably should be cast steel having a grade of ASTM A-27 GRADE 70-40 [485-275] (UNS 702501) or SCW480 or equivalent to be serviceable.

Although the present invention has been described in conjunction with specific embodiments, those of ordinary skill in the art will appreciate the modifications and variations that can be made without departing from the scope and the spirit of the present invention. 

What is claimed is:
 1. An intermodal shipping container comprising one or more intermediate gable posts and/or intermediate gable headers adapted to increase an internal width and strength of the container, wherein the gable posts and/or the gable headers include twin channels having at least two internal flanges welded to a gable post plate and/or gable header plate.
 2. The intermodal shipping container as recited in claim 1, wherein the twin channels are one piece and welded to the one or more gable posts or gable headers, wherein the gable post or the gable headers have slots allowing the welding of the one-piece twin channel from the interior.
 3. The shipping container as recited in claim 2, wherein wall panel extensions are integrated in the one-piece twin channels, providing a flat interior profile.
 4. The shipping container as recited in claim 2, wherein the one-piece twin channel is formed by rolling or pressing.
 5. An intermodal shipping container comprising one or more upper castings having an integral top rail ledge, wherein a top rail of a side wall hangs on the integral top rail ledge.
 6. The intermodal shipping container as recited in claim 5, wherein the one or more upper castings have a first protrusion and a second protrusion, the first protrusion engaging with a twin channel intermediate gable post and the second protrusion engaging with an twin channel intermediate gable header.
 7. An intermodal shipping container comprising “C” shaped channel beam main frame cross members.
 8. The intermodal shipping container as recited in claim 7, wherein the crossmembers are adapted to provide a web oriented to face a front of the shipping container, the web dimensions of the crossmembers being one continuous length.
 9. The intermodal shipping container as recited in claim 7, wherein the crossmembers include a wide uninterrupted flange to receive floor screws.
 10. An intermodal shipping container comprising a one-piece continuous top plate including an integral lip connecting the top plate and a roof.
 11. The intermodal shipping container as recited in claim 10, wherein the top plate is a door header top plate.
 12. The intermodal shipping container as recited in claim 10, wherein the top plate is a front top plate.
 13. The intermodal shipping container as recited in claim 11, further comprising an overhang adapted to shield upper door lock rod keepers.
 14. The shipping container as recited in claim 10, the container further comprising rear headers, wherein the rear headers have integral internal gussets.
 15. An intermodal shipping container comprising one or more rear lower castings, wherein the one or more rear lower castings are an integral interlocking interface, wherein a door sill abuts the rear lower casting and a rear corner post, the one or more rear lower castings having an observation hole to externally view a chassis twist lock.
 16. An intermodal shipping container comprising a bolster including an integral seating and fastening surface and slots, the integral seating and fastening surface adapted to fasten and support flooring and the slots used for welding, wherein the bolster is flush with a top surface of flooring.
 17. The shipping container as recited in claim 16, wherein the bolster is a front intermediate bolster
 18. The shipping container as recited in claim 16, wherein the bolster is a rear intermediate bolster.
 19. The shipping container as recited in claim 16, wherein the bolster is a door sill.
 20. The shipping container as recited in claim 16, wherein the bolster has integral internal gussets.
 21. An intermodal shipping container comprising one or more nested rear corner posts subassemblies, the one or more nested rear corner posts having a notch and protrusion connection, wherein a protrusion in a lower rear casting engages with a corresponding notch in the rear corner post.
 22. A method of fabricating an intermodal shipping container, the method comprising: preparing a sub assembly by welding a top rail onto a side wall panel; introducing the side wall sub assembly to intermediate gables from above; and lowering the wall sub assembly until the wall assembly is entirely supported by the intermediate gables. 